In commercially available gas measuring probes, such as that described in U.S. Pat. No. 3,928,161, assigned to the assignee of the present invention and incorporated herein by reference, which employ a solid electrolyte electrochemical cell having electrodes disposed on opposite surfaces thereof, the electrodes, which are typically platinum, undergo a physical deterioration when exposed to reducing industrial atmospheres containing sulfur compounds and highly corrosive flue gases. The disintegration or deterioration of the electrode results in a loss of contact with the solid electrolyte substrate which in turn results in an increase in cell resistance.
In oxygen analyzer probes such as that described in the above-identified U.S. Patent, wherein the solid electrolyte electrochemical cell is in the form of a disc which is secured within a tubular member by a noble metal braze, the braze exhibits the same characteristics as the cell electrode and assumes the function of an additional oxygen electrode when the electronic conductivity across a cell electrode diminishes due to cell electrode deterioration. This condition results in an electrolytic leakage current through the electrolyte near the braze which changes the EMF produced by the electrochemical cell.